Cooling system with a coolant pump for an internal combustion engine

ABSTRACT

A method is disclosed for operating a cooling system with a coolant pump for an internal combustion engine. The coolant pump is operated for a preset period of time after a starting of the internal combustion engine. The cooling system is switched over into a first warming-up operating mode, in which the coolant pump is not operated, in the case that a first warming-up condition is fulfilled.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to German Patent Application No. 102015006303.0, filed May 16, 2015, which is incorporated herein by reference in its entirety.

TECHNICAL FIELD

The present disclosure pertains to a cooling system with a coolant pump for an internal combustion engine, a method for operating the cooling system, a motor vehicle with the cooling system and to a computer program product for carrying out the method.

BACKGROUND

WO 03/106825 A1 discloses a method for operating a liquid-cooled internal combustion engine, with which an electric coolant pump is briefly operated for a period of time following detection of a cold start and is always deactivated again following the expiration of the period of time. For as long as a coolant temperature is below a threshold value, the coolant pump is then activated with alternating delivery direction. As soon as the coolant temperature reaches the threshold value, the coolant pump is activated in such a manner that a continuous coolant flow is obtained, and an control valve is activated as a function of the coolant temperature in order to flow through a bypass with an oil-coolant heat exchanger and at higher coolant temperature also a cooler.

SUMMARY

In accordance with the present disclosure the operation of a cooling system for an internal combustion engine, in particular of a motor vehicle is improved. According to an aspect of the present disclosure, a cooling system for an internal combustion engine, in particular a cooling system of a motor vehicle, in particular of a passenger car, includes a coolant pump for delivering or circulating a liquid coolant, in particular cooling water through one or more coolant lines. The internal combustion engine in an embodiment is a spark-ignition or diesel engine and may include an exhaust gas turbocharger. In an embodiment, the coolant pump is an electronic or electrically-actuated coolant pump. Because of this, it can be advantageously operated independently of the internal combustion engine.

In an embodiment, the cooling system includes an electrically actuated control valve, in particular rotary control valve, can be opened and closed, in particular variably opened and closed through which in an embodiment optionally or dependent on position, a radiator line, in which a radiator or ambient coolant heat exchanger is arranged, and/or beforehand a bypass line which is parallel with respect to the radiator line in terms of flow, in which in an embodiment an oil-coolant heat exchanger is arranged. In an embodiment, the cooling system includes a heater line that is independent of the control valve and/or parallel with respect to the radiator and/or bypass line in terms of flow, in which a heater or interior coolant heat exchanger is arranged.

In an embodiment, the cooling system includes a coolant temperature sensor for detecting a coolant temperature, which can be arranged in particular upstream in front of the control valve, downstream after the control valve or in the control valve. Additionally or alternatively, the cooling system, in an embodiment, includes a reference temperature sensor for detecting a reference temperature, in particular a material and/or component temperature. The reference temperature, in an embodiment, can he an in particular critical, in particular maximum temperature of a component of the internal combustion engine or of another component of the motor vehicle or a temperature dependent on the former, for example a cylinder head or turbocharger temperature. The reference temperature can additionally or alternatively, in an embodiment, he determined, in particular calculated also in particular in a model-supported or model-based manner, for example based on kinematic or kinetic parameters of the internal combustion engine or of the motor vehicle such as for example a torque, a rotational speed and/or a travelling speed. By way of a reference temperature sensor, the reference temperature, in an embodiment, can be advantageously detected precisely and/or reliably. Through a model-based determination, the reference temperature, in an embodiment, can be advantageously determined easily, in particular without a sensor (directly) measuring the same.

A method for operating a cooling system with a coolant pump for the internal combustion engine according to an aspect of the present disclosure is disclosed. The coolant pump is operated for a preset period of time following a starting of the internal combustion engine. Then, the cooling system is switched over into a warming-up operating mode, in which the coolant pump is not operated, in the case a warming-up condition is fulfilled. The cooling system may be equipped in terms of hardware and/or software for carrying out a method described herein. In particular, a pump controller is configured to operate the coolant pump for a preset period of time after a starting of the internal combustion engine, then switch over the cooling system into a warming-up operating mode, in which the coolant pump is not operated, in the case that a warming-up condition is fulfilled. Through the initial operation of the coolant pump for a period of time that is preset in a fixed or variable manner, as a function of a temperature of an ambient, coolant in the internal combustion engine and/or motor vehicle can be advantageously distributed and/or circulated following a starting of the internal combustion engine, coolant, and thus a homogeneous temperature distribution be achieved.

Through the following switching-over into the warming-up operating mode, in which the coolant pump is not operated, the coolant pump, in an embodiment, is advantageously, in particular only stopped or deactivated as a function of the warming-up condition when required in order to achieve a more rapid warming-up of the internal combustion engine and/or of the coolant through the internal combustion engine. In the following, this warming-up operating mode is described as first warming-up operation mode without restriction of the generality, this warming-up condition accordingly as first warming-up condition.

In an embodiment, the bypass and/or the radiator line may be blocked or closed in the first warming-up operating mode at least substantially completely through the control valve, which for this purpose will be or is suitably activated. Accordingly, in an embodiment, the cooling system includes a valve or other means for closing the bypass and/or radiator line and/or the control valve in the first warming-up operating mode, Because of this, the coolant, in an embodiment, can be advantageously warmed up even more rapidly.

The first warming-up condition is fulfilled in an embodiment in the case or provided that a coolant temperature undershoots a preset first limit value. In other words, the coolant pump, in an embodiment, is only shut down following the expiration of the preset period of time in the case it is detected that the coolant temperature undershoots a preset first limit value.

The cooling system is switched over into a closed-loop control mode, in which the coolant pump and/or a or the control valve of the cooling system is open-loop controlled or closed-loop controlled, instead of the first warming-up operating mode or following the initial operating of the coolant pump for a preset period of time after a starting of the internal combustion engine, in the case that the warming-up condition is not fulfilled. Accordingly, the cooling system, in an embodiment, includes valve, switch or other means for switching over the cooling system into a closed-loop control mode, in which the coolant pump and/or the control valve of the cooling system is open-loop controlled or closed-loop controlled, instead of the first warming-up operating mode, in the case that the warming-up condition is not fulfilled. Because of this, in an embodiment, it is possible to advantageously change to or switch over into the closed-loop control mode directly or immediately, in particular without prior shutting down of the coolant pump in the case or provided that the first warming-up condition upon or after expiration of the preset period of time is not fulfilled.

In the closed-loop control mode, the coolant pump, in an embodiment, is open-loop controlled and the control valve is closed-loop pre-controlled in each case based on a preset requested or set point temperature, in particular coolant temperature. In another embodiment, the control valve, in the closed-loop control mode, is open-loop controlled and the coolant pump is closed-loop pre-controlled in each case based on a preset requested or set point temperature, in particular coolant temperature. Because of this, an undesirable feedback or mutual influencing can be advantageously reduced, in particular prevented. Equally, both coolant pump and also control valve can each be or are open-loop controlled or closed-loop controlled in the closed-loop control mode, in particular closed-loop pre-controlled

In an embodiment, the cooling system may be switched over from the first warming-up operating mode into the closed-loop control mode or a second warming-up operating mode, in which the coolant pump is operated pulsed or with a preset rotational speed in the case that a second warming-up condition is fulfilled. Accordingly, the cooling system, in an embodiment, includes a valve, switch or other means for switching over the cooling system from the first warming-up operating mode into the closed-loop control mode or a second warming-up operating mode, in which the coolant pump is pulsed or operated with a present rotational speed in the case that a second warming-up condition is fulfilled.

The preset rotational speed, in an embodiment, is maximally 10% greater than a minimum rotational speed of the coolant pump brought about as a result of design, flow and/or drive. In other words, the coolant pump, in an embodiment, is operated, in the second warming-up operating pump, approximately with its minimum rotational speed. Because of this, the coolant that has already been heated up in the first warming-up operating mode can be advantageously distributed or circulated in an embodiment.

By operating the coolant pump in a pulsed or periodic manner, such advantageous circulation can be realized, in an embodiment, also with coolant pumps the minimum rotational speed of which is too high. In addition or alternatively, the pulsed operating, in an embodiment, can bring about a circulation that is advantageous in terms of flow and/or heat.

In an embodiment, a pulse width of the pulsed operating is preset as a function of a kinematic or kinetic parameter of the internal combustion engine, in particular a torque and/or a rotational speed, a temperature, in particular a coolant temperature, and/or a flow parameter of the internal combustion engine, in particular an air and/or fuel mass or volumetric flow. Accordingly, the cooling system, in an embodiment, includes a controller or other means for presetting a pulse width of the pulsed operating as a function of a kinematic or kinetic parameter of the internal combustion engine, in particular a torque and/or a rotational speed, a temperature, in particular the coolant temperature, and/or a flow parameter of the internal combustion engine, in particular an air and/or fuel mass or volumetric flow. For example, with greater torque, higher rotational speed, higher coolant temperature, greater air and/or fuel mass or volumetric flow a greater pulse width can be preset in order to deliver more coolant in this way.

In an embodiment, the control valve will he or is controlled into a preset position into the second warming-up operating mode, in particular the bypass and/or the radiator line, at least substantially completely blocked or closed. Accordingly, the cooling system, in an embodiment, includes controller, switch or other means for controlling the control valve into a preset position for closing the control valve, in the second warming-up operating mode. By way of an at least substantially completely closed control valve, the coolant, in an embodiment, can be advantageously heated up more rapidly, by way of a partly opened control valve or an at least partly opened bypass line, the oil-coolant heat exchanger advantageously utilized or operated already in the second warming-up operating mode.

The second warming-up condition, in an embodiment, is fulfilled in the case or provided that at least one or the reference means temperature exceeds a preset second limit value or at least a kinematic or kinetic parameter of the internal combustion engine or of the motor vehicle with the internal combustion engine exceeds a preset parameter limit value, in particular a torque of the internal combustion engine exceeds a torque limit value, a rotational speed of the internal combustion engine undershoots a rotational speed limit value or a travelling speed of the motor vehicle exceeds a travelling speed limit value. In other words, the coolant pump, in an embodiment, starting out from the first warming-up operating mode, is again operated in the case that it is detected that the reference temperature exceeds a preset second limit value or a kinematic or kinetic parameter of the internal combustion engine or of the motor vehicle exceeds a preset perimeter limit value. Because of this a certain minimum cooling through the coolant circulated by the coolant pump can be advantageously ensured in an embodiment in the case that critical, reference, in particular material or component temperature or a kinematic or kinetic parameter of the internal combustion engine or of the motor vehicle require this.

In an embodiment, the cooling system is switched over from the second warming-up operating mode into the closed-loop control mode in the case that a third warming-up condition is fulfilled. Additionally or alternatively, the method, in an embodiment the cooling system is switched over from the second warning-up operating mode into the first warming-up operating mode in the case that a fourth warming-up condition is fulfilled. Accordingly, the cooling system, in an embodiment, includes means for switching over the cooling system from the second warming-up operating mode into the closed-loop control mode, in the case that a third warming-up condition is fulfilled, and/or means for switching over the cooling system from the second warming-up operating mode into the first warming-up operating mode in the case that a fourth warming-up condition is fulfilled.

As already explained above, it is possible to switch over, in an embodiment, from the first warming-up operating mode directly into the closed-loop control mode in the case that the second warming-up condition is fulfilled, or in another embodiment, it is possible instead to initially switch over from the first warming-up operating mode into the second warming-up operating mode in the case that the second warming-up condition is fulfilled. In this embodiment it is then possible to advantageously switch over from the second warming-up operating mode into the closed-loop control mode in the case that the third warming-up condition is fulfilled.

The third warming-up condition is fulfilled in an embodiment in the case or provided that at least one or the coolant temperature exceeds a preset third limit value or at least one kinematic or kinetic parameter of the internal combustion engine or of the motor vehicle with the internal combustion engine exceeds a preset parameter limit value, in particular a torque of the internal combustion engine exceeds one or the torque limit value, a rotational speed of the internal combustion engine exceeds one or the rotational speed limit value or a travelling speed of the motor vehicle exceeds one or the travelling speed limit value. In other words, switching over into the closed-loop control mode is performed in an embodiment, starting out from the second warming-up operating mode, in the case it is detected that the coolant temperature exceeds a preset third limit value or a kinematic or kinetic parameter of the internal combustion engine or of the motor vehicle exceeds a preset parameter limit value.

The preset third limit value, in an embodiment, is smaller by a preset deduction than the requested or set point temperature. Because of this, it is possible, in an embodiment, to change over with an offset into the closed-loop control mode so that the closed-loop control of the coolant pump and/or of the control valve advantageously responds in particular more rapidly. Additionally or alternatively, a loading of the cooling system and/or of the internal combustion engine through peak deflections as a consequence of pulsed operation of the coolant pump can be advantageously reduced.

The fourth warming-up condition, in an embodiment, is fulfilled in the case or provided that the coolant temperature undershoots a preset fourth limit value. In other words, starting out from the second warming-up operating mode, switching back or switching-over, in an embodiment, into the first warming-up operating mode is again performed in the case that it is detected that the coolant temperature undershoots a preset fourth limit value. By switching back into the first warming-up operating mode, in which the coolant pump is not any longer operated, the operation of the cooling system can be advantageously improved, in particular a warming-up of the coolant optimized.

In an embodiment, the control valve is checked before an initial operating of the coolant pump or before the coolant pump is operated for a preset period of time after a starting of the internal combustion engine. If the check reveals that the control valve does not properly function or operate, a message can be output in an embodiment and/or an operation of the internal combustion engine restricted, in particular prevented. Accordingly, the cooling system, in an embodiment, includes a sensor, controller or other means for checking the control valve before the initial operating of the coolant pump after the starting of the internal combustion engine, and in a further development, a display, signaling device, controller or other means for outputting a message and/or for restricting in particular preventing an operation of the internal combustion engine in the case that the check reveals that the control valve does not properly function or operate. Checking the control valve may include moving into one or more positions of the control valve and the comparison of the respective precision currently reached with the preset position or position to he moved to, in particular an at least substantially completely opened and/or an at least substantially completely closed position.

In an embodiment, the coolant pump is operated for a preset period of time after switching off the internal combustion engine. This period of time and/or an operation, in particular a rotational speed of the coolant pump can be preset in an embodiment in a fixed or variable manner, in particular as a function of a temperature, in particular an ambient, coolant, internal combustion engine and/or motor vehicle temperature. Accordingly, the cooling system in an embodiment includes means for operating the coolant pump for a preset period of time after switching off the internal combustion engine and in a further development means for presetting the period of time and/or of the operation, in particular a rotational speed of the coolant pump as a function of a temperature, in particular an ambient, coolant, internal combustion engine and/or motor vehicle temperature. Through such a temperature-dependent coast operation of the coolant pump in terms of time and/or rotational speed, a thermal loading of the internal combustion engine and/or of the motor vehicle can be advantageously reduced in an embodiment.

In an embodiment, the changeover into the closed-loop control mode is always carried out when at least one kinematic or kinetic parameter of the internal combustion engine or of the motor vehicle with the internal combustion engine exceeds a preset parameter value, in particular a torque of the internal combustion engine exceeds a or the torque limit value, a rotational speed of the internal combustion engine exceeds a or the rotational speed limit value or a travelling speed of the motor vehicle exceeds a or the travelling speed limit value.

In an embodiment, the cooling system is switched over into a preset operating mode as a function of a heater request and of a temperature. Accordingly, the cooling system, in an embodiment, includes valve, controller or other means for switching over the cooling system into a preset operating mode as a function of a heater request and of a temperature. By switching over into a preset operating mode as a function of or as a consequence of a detection, a heater request or a request of a heat output, in particular of a minimum heat output, or an operation, in particular of a minimum operation, of the heater, heater output or heat for heating an interior of the motor vehicle can be advantageously made available in an embodiment. Accordingly, a heater request in this case is to mean a detected request of a heat output of at least one preset minimum heat output, or an operation at least one preset minimum operation of the heater.

In an embodiment, switching over is performed as a function of a heater request and the reference temperature out of the first warming-up operating mode, in which the coolant pump is not operated, into the second warming-up operating mode, in which the coolant pump is operated pulsed or with a preset rotational speed, in particular, provided or in the case a heater request is detected or is present and the reference temperature exceeds a preset limit value, which for this distinguishing further limit values without restriction of the generality is described as fifth limit value. This switching over can take place in particular independently or additionally to a switching over as a consequence of the fulfilled second warming-up condition. Because of this, switching over into the second warming-up operating mode can be advantageously performed in an embodiment when a heater request is detected and already heated coolant can thus be actively supplied to the heater.

Accordingly, the cooling system, in an embodiment, includes switch, controller or other means for switching over the cooling system as a function of a heater request and of the reference temperature from the first warming-up operating mode, in which the coolant pump is not operated, into the second warming-up operating mode, in which the coolant pump is operated pulsed or with a preset rotational speed.

Additionally or alternatively switching over into a heater operating mode is performed in an embodiment as a function of a heater request and of the coolant temperature, in which the coolant pump is continuously operated with a heater request-dependent preset and/or constant rotational speed, in particular from the second warming-up operating mode, in which the coolant pump is operated pulsed or with a rotational speed preset independently of a heater request, in particular provided that or in the case a heater request is detected or present and the coolant temperature exceeds a preset limit value, which for distinguishing further limit value without restriction of the generality is described as sixth limit value. In a further development, switching over into the heater operating mode is performed only after a preset period of time following detecting the heater request and exceeding the sixth limit value. Because of this, it is advantageously possible to initially circulate coolant for the preset period of time in the second warming-up operating mode, thus improving the warming-up. By way of a heater operating mode, in which the coolant pump is operated with a rotational speed preset independent of a heater request and/or constant rotational speed and/or continuously, the heater, in an embodiment, can be advantageously supplied with coolant.

The rotational speed of the coolant pump that is preset independently of a heater request in the heater operating mode rises in an embodiment with a percentage heater request, in particular linearly and/or in discrete jumps. Accordingly, a maximum possible heater request or requestable heater output, for example for 5-25%, a first constant rotational speed of the coolant pump can be preset for a first percentage range, for a higher second range, approximately 25-50% a greater second, in particular constant rotational speed of the coolant pump, for an even higher third range, approximately 50-75% an even greater third, in particular constant rotational speed of the coolant pump and for an even higher fourth range, approximately 75-100% an even greater fourth, in particular constant rotational speed of the coolant pump.

Accordingly, the cooling system in an embodiment includes a switch, controller or other means for switching over the cooling system as a function of a heater request and of the coolant temperature in a heater operating mode, in which the coolant pump is operated with a rotational speed that is preset independently of a heater request and/or constant and/or continuously from the second warming-up operating mode, in which the coolant pump is operated pulsed or with a rotational speed that is preset independently of a heater request

Additionally or alternatively, it is possible to switch over from the first warming-up operating mode into the heater operating mode as a function of a heater request and the coolant or reference temperature in the case no second warming-up operating mode is provided in an embodiment

In an embodiment, the radiator line of the cooling system, in which the radiator is arranged, and/or the bypass line of the cooling system, in which the oil-coolant heat exchanger will be or is arranged, is closed or opened in particular temperature-dependently. Accordingly, the cooling system, in an embodiment, includes a valve, controller or other means for the temperature-dependent closing or opening of the radiator line and/or of the bypass line in the heater operating mode. By way of a closed radiator line, more heat can be advantageously supplied to the heater in an embodiment in the heater operating mode. By way of a closed bypass line, the heater in the heater operating mode can be advantageously supplied with even more heat in an embodiment. By way of an at least partly opened bypass line, heat can also be advantageously supplied to the oil-coolant heat exchanger in the heater operating mode in an embodiment.

In an embodiment, the cooling system is switched over as a function of the coolant temperature from the heater operating mode into the first warming-up operating mode, in particular in the case or provided that the coolant temperature undershoots a preset limit value, which for distinguishing further limit values without restriction of the generality is described as seventh limit value. In an embodiment, the seventh limit value is smaller by a preset hysteresis deduction than the sixth limit value, in order to avoid excessively frequent switching over.

Accordingly, the cooling system, in an embodiment, includes a switch, controller or other means for switching the cooling system over from the heater operating mode into the first warming-up operating mode as a function of the coolant temperature.

In an embodiment, switching over from the heater operating mode, in which the coolant pump and/or a or the control valve of the cooling system is open-loop controlled or closed-loop controlled, is performed in the case that a fifth warming-up condition is fulfilled. Accordingly, the cooling system, in an embodiment, includes a switch, controller or other means for switching over the cooling system from the heater operating mode into the closed-loop control mode, in which the coolant pump and/or a or the control valve of the cooling system is open-loop controlled or closed-loop controlled, in the case that a fifth warming-up condition is fulfilled. The fifth warming-up condition can correspond to the third warming-up condition or be in accordance with the same.

The fifth warming-up condition is fulfilled in an embodiment in the case or provided that at least one or the coolant temperature exceeds a preset limit value, in particular the third limit value explained in the following, or at least one kinematic or kinetic parameter of the internal combustion engine or of the motor vehicle with the internal combustion engine exceeds a preset parameter limit value, in particular a torque of the internal combustion engine exceeds a torque limit value, a rotational speed of the internal combustion engine exceeds a rotational speed limit value or a travelling speed of the motor vehicle exceeds a travelling speed limit value.

A means in terms of the present disclosure may be of hardware and/or software design, in particular include an in particular digital processing, in particular microprocessor unit (CPU) which is preferentially data or signal connected to a storage and/or bus system and/or one or more programs or program modules. The CPU can be designed in order to execute commands which are implemented as a program stored in a storage system, detect input signals from a data bus and/or emit output signals to a data bus. A storage system can include one or more, in particular different storage media, in particular optical, magnetic, solid state and/or other non-volatile media. The program can be of such a nature that it embodies or is capable of carrying out the method described here, so that the CPU can execute the steps of such methods and thus in particular operate a cooling system.

One or more steps of the method are, in an embodiment, executed in a completely or partly automated manner.

BRIEF DESCRIPTION OF THE DRAWINGS

The present disclosure will hereinafter be described in conjunction with the following drawing figures, wherein like numerals denote like elements.

FIG. 1 shows a cooling system and an internal combustion engine of a motor vehicle according to an embodiment of the present disclosure

FIG. 2 illustrates a method for operating the cooling system according to an embodiment of the present disclosure; and

FIG. 3 illustrates a method for operating the cooling system according to a further embodiment of the present disclosure.

DETAILED DESCRIPTION

The following detailed description is merely exemplary in nature and is not intended to limit the invention or the application and uses of the invention. Furthermore, there is no intention to be bound by any theory presented in the preceding background of the invention or the following detailed description.

FIG. 1 shows an internal combustion engine 1 and a cooling system of a motor vehicle which is not otherwise shown according to an embodiment of the present disclosure.

The cooling system includes an electric coolant pump 2, a rotary control valve 3, a heater line L1 that is independent of the rotary control valve 3 with a heater 4 for heating an interior of the motor vehicle by way of a coolant that is circulated or delivered by the coolant pump 2, a bypass line L2 that is parallel in terms of flow with the heater line L1 with an oil-coolant heat exchanger 5 and a radiator line L3 that is parallel in terms of flow with the bypass line L2 with a radiator 6.

By way of the rotary control valve 3, the radiator line L3 and beforehand the bypass line L2 can be variably opened and shut off optionally or dependent on position. In other words, the bypass line L2 is opened when the radiator line L3 is opened or open.

The cooling system includes a coolant temperature sensor 7 for detecting a coolant pump T, which is arranged between the heater line L1 and an outlet of the rotary control valve 3, in a modification that is not shown in the rotary control valve 3.

Additionally, the cooling system includes a reference temperature sensor 8 for detecting a reference temperature in the form of a cylinder head temperature T_(mat). The reference temperature T_(mat) is a critical temperature of the internal combustion engine that is highest during the operation.

The cooling system, furthermore includes an engine control unit or controller or simply ECU 9, which carries out a method as described hereinafter with reference to FIG. 2. 3 for operating the cooling system according to an embodiment of the present disclosure. In other words, the system is equipped for this purpose in terms of hardware and software and is connected to the electric coolant pump 2, the rotary control valve 3, the coolant temperature sensor 7 and the reference temperature 8 in particular in terms of signals, as indicated in a dashed-dotted form in FIG. 1. The ECU 9 open-loop controls or closed-loop controls the coolant pump 2 and the rotary control valve 3 and receives the coolant temperature T_(cool) and the cylinder head temperature T_(mat) the coolant temperature sensor 7 and the reference temperature sensor 8 respectively.

In a modification that is not shown, the reference and cylinder head temperature T_(mat) is not measured but may be calculated by the ECU 9 on the basis of a model. Accordingly, the reference temperature sensor 8 can be omitted in this modification.

A method carried out by the ECU 9 for operating the cooling system according to an embodiment of the present disclosure, which is shown in FIG. 2, includes a first step S10 in which it is checked if the internal combustion engine was started. For as long as this is not the case (S10: “N”), the check is periodically repeated. If the internal combustion engine was started (S10: “Y”), the control valve 3 is Checked in a step S20. If the check shows that the control valve 3 does not properly function or operate (S20: “N”), a message is output in a step S30 and/or operation of the internal combustion engine 1 is restricted, in particular prevented.

In the case that the ECU 9 determines that the control valve 3 functions properly (S20: “N”), it proceeds with step S40. In the same, it operates the coolant pump 2 for a period of time ×0 preset fixed or variable as a function of a temperature, in particular of an ambient, coolant, internal combustion engine and/or motor vehicle temperature following the starting of the internal combustion engine I. Following this, the ECU 9 checks in a subsequent step S50 if a first warming-up condition is fulfilled by checking if the coolant temperature T_(cool) detected by the coolant temperature sensor 7 undershoots a preset first limit value When the ECU 9 in step S50 detects that the coolant temperature undershoots the first limit value (T_(cool)<T_(thld)

S50: “Y”), it proceeds with step S70, otherwise (S50: “N”) with step S60.

In step S60, the ECU 9 executes a closed-loop control mode, in which the coolant pump 2 is open-loop controlled and the rotary control valve 3 closed-loop pre-controlled, in particular in each case based on a preset requested or set point coolant temperature T_(request). If by contrast the first warming-up condition is fulfilled (S50: “Y”), the ECU 9 in step S70 switches over to a first warming-up operating mode. In the same, the coolant pump 2 is not operated. The bypass and the radiator line L2, L3 are completely shut off in the first warming-up mode by the control valve 3 which is suitably controlled by the ECU 9 for this purpose,

Following this, the ECU 9 in a subsequent step S80 checks if a second warming-up condition is fulfilled by checking if the reference or cylinder head temperature T_(mat) exceeds a preset second limit value T_(thld1) or a torque M of the internal combustion engine 1 exceeds a torque limit value M_(thld) or a rotational speed n of the internal combustion engine 1 exceeds a rotational speed limit value n_(thld) or a travelling speed v of the motor vehicle exceeds a travelling speed limit value v_(thld). Here, exceeding one of these limit values is sufficient in order for the second warming-up condition to be fulfilled (T_(mat)>T_(thld1) OR M>M_(thld) OR n>n_(thld) OR v>v_(thld)).

If the ECU 9 in step S80 detects that the second warming-up condition is fulfilled (S80: “Y”), it proceeds with step S90, otherwise (S80: “N”) it returns to step S70 and continues executing the first warming-up operating mode. In step S90, the ECU 9 executes a second warming-up operating mode, in which the coolant pump 2 is operated in a pulsed manner. The control valve 3 in the second warming-up operating mode is controlled into a preset position, in which it shuts off in an exemplary embodiment the bypass and the radiator line L2, L3, in another exemplary embodiment, only opens the bypass line L2 and shuts off the radiator line L3. The ECU 9 can preset a pulse width of the pulsed operating in step S90 as a function of a torque and/or of a rotational speed of the internal combustion engine, of the coolant temperature T_(cool) and/or an air and/or fuel mass or volumetric flow.

Following this, the ECU 9 in a subsequent step S100 checks if a third warming-up condition is fulfilled by checking if the coolant temperature T_(cool) exceeds a preset third limit value T_(request)-T_(thld6) or the torque M exceeds the torque limit value M_(thld) or the rotational speed n exceeds the rotational speed limit value n_(thld) or the travelling speed v exceeds the travelling speed limit value v_(thld). Here, exceeding one of these limit values is again already sufficient for the fourth warming-up condition to be fulfilled (T_(cool)>T_(request)-T_(thld6) OR M>M_(thld) OR n>n_(thld) OR v>v_(thld)). If the ECU 9 in step S100 detects that the third warming-up condition is fulfilled (S100: “Y”), it proceeds with S60, i.e. switches over into the closed-loop control mode, otherwise (S100: “N”) it proceeds with step S120. As indicated by T_(request)-T_(thld6), the third limit value is smaller by a preset deduction T_(thld6) than the requested set point coolant temperature T_(request).

In step S120 the ECU 9 Checks if a fourth warming-up condition is fulfilled by checking if the coolant temperature T_(cool) undershoots a preset fourth limit value T_(thld5)-T_(Hyst). If the ECU 9 in step S120 detects ⁻that the fourth warming-up condition is fulfilled (S120: “Y”), it returns to step S70 and again executes the first warming-up operating mode, otherwise (S120: “N”) it returns to step S90 and continues executing the second warming-up operating mode.

In a step S130 following step S60, the ECU 9 Checks if the internal combustion engine 1 continues running or is fueled. For as long as this is the case (S130: “Y”) it remains in the closed-loop control mode. If by contrast the ECU 9 determines in step S130 that the internal combustion engine 1 is no longer running or (has been) switched off (S130: “N”) it proceeds with step S140 in which it operates the coolant pump 2 for a preset period of time following the switching off of the internal combustion engine 1, This period of time and/or the rotational speed of the coolant pump 2 can be preset in an embodiment fixed or variably, in particular as a function of a temperature, in particular an ambient, coolant, internal combustion engine and/or motor vehicle temperature.

Following this, i,e, following the expiration of this preset period of time, the ECU 9 or the method returns to step S10.

It is evident that on exceeding the torque, rotational speed or travelling speed limit value it is possible to switch over in a manner of speaking through the second warming-up mode in a “through-connected” and direct manner when in FIG. 2 the steps S80 and S100 are answered in the affirmative (“Y”).

A method carried out by the ECU 9 for operating the cooling system according to a further embodiment of the present disclosure, which is shown in FIG. 3, partly corresponds to the method explained above with reference to FIG. 2, wherein same features are identified by identical reference characters.

Once the internal combustion engine has been started (S10: “Y”), the control valve 3 is checked in a step S20, If the check shows that the control valve 3 does not properly function or operate (S20: “N”), a message is output in a step S30 and/or an operating of the internal combustion engine 1 restricted, in particular prevented. In the case that the ECU 9 determines that the control valve 3 functions properly (S20: “N”), it proceeds with step S40.

In the same, it operates the coolant pump 2 for a period of time ×0 preset fixed or variable as a function of a temperature, in particular of an ambient, coolant, internal combustion engine and/or motor vehicle temperature after the starting of the internal combustion engine 1. Following this, the ECU 9 checks in a subsequent step S50 if a first warming-up condition is fulfilled by checking if the coolant temperature T_(cool) detected by the coolant temperature sensor 7 undershoots a preset first limit value T_(thld).

If the ECU 9 in step S50 detects that the coolant temperature T_(cool) undershoots (T_(cool) <T_(thld)z,900 S50: “Y”) the first limit value T_(thld,) it proceeds with step S70, otherwise (S50: “N”) with step S60. In step S60, the ECU 9 executes a closed-loop control mode in which the coolant pump 2 is open-loop controlled and the rotary control valve 3 closed-loop pre-controlled, in particular in each case based on a preset requested or set point coolant temperature T_(request). If by contrast the first warming-up condition is fulfilled (S50: “Y”), the ECU 9 in step S70 switches over into a first warming-up operating mode. In the same, the coolant pump 2 is not operated. The bypass and the radiator line L2, L3 are completely shut off in the first warming-up operating mode by the control valve 3 that is suitably controlled by the ECU 9 for this purpose.

Following this, the ECU 9 in a subsequent step S80 checks if a second warming-up condition is fulfilled by checking if the reference or cylinder head temperature T_(mat) exceeds a preset second limit value T_(thld1) or a torque M of the internal combustion engine 1 exceeds a torque limit value M_(thld) or a rotational speed n of the internal combustion engine 1 exceeds a rotational speed limit value n_(thld) or a travelling speed v of the motor vehicle exceeds a travelling speed limit value v _(thld) Here, exceeding one of these limit values is already sufficient for the second warming-up condition to be fulfilled (T_(mat)>T_(thld) OR M>M_(thld) OR n>n_(thld) Or v>v_(thld)).

If the ECU 9 in step S80 detects that the second warming-up condition is fulfilled or a heater request was detected and the reference temperature I_(mat) exceeds (S80: “Y”) a preset fifth limit value T_(thld3), it proceeds with step 890, otherwise (S80: “N”) it returns to step S70 and continues executing the first warming-up operating mode. In step S90, the ECU 9 executes a second warming-up operating mode in which the coolant pump 2 is operated in a pulsed manner. The control valve 3 is controlled in the second warming-up operating mode into a preset position, in which it shuts off in an exemplary embodiment the bypass and the radiator line L2, L3, in another exemplary embodiment, only opens the bypass line L2 and shuts off the radiator line L3, The ECU 9 can preset a pulse width of the pulsed operating in step 890 as a function of a torque and/or of a rotational speed of the internal combustion engine, of the coolant temperature I_(cool) and/or an air and/or fuel mass or volumetric flow.

Following this, the ECU 9 in a subsequent step S100 checks if a third warming-up condition is fulfilled by checking if the coolant temperature T_(cool) exceeds a preset third limit value T_(request)-T_(thld) or the torque M exceeds the torque limit value M_(thld) or the rotational speed n exceeds the rotational speed limit value n_(thld) or the travelling speed v exceeds the travelling speed limit value v_(thld). Here, exceeding one of these limit values is already sufficient for the fourth warming-up condition to be fulfilled (T_(cool)>T_(request)-T_(thld6) OR M>M_(thld) OR n >n_(thld) OR v>v_(thld) ). If the ECU 9 in step S100 detects that the third warming-up condition is fulfilled (S100: “Y”), it proceeds with S60, i.e. switches over into the closed-loop control mode, otherwise (S100: “N”) it proceeds with step S110. As indicated by T_(request)-T_(thld6) third limit value is smaller by a preset: deduction T_(thld6) than the requested set point coolant temperature T_(request).

In step S110, the ECU 9 Checks if a heater request is present or was detected, the coolant temperature T_(cool) exceeds a preset sixth limit value T_(thld5) and at least one preset period of time ×1 has passed since the detection of the heater request and of the exceeded sixth limit value. If this is the case (S110: “Y”), the ECU 9 in a step S150 switches over into a heater operating mode, otherwise (S110: “N”) it proceeds with step S120.

In the heater operating mode or step S150, the coolant pump 2 is continuously operated with a constant rotational speed preset as a function of a heater request. The rotational speed preset as a function of a heater request is for example stored in a characteristic diagram and rises with an in particular percentage heater request, in particular linearly and/or in discrete jumps. In the heater operating mode, or step S150, the radiator line L3 is or will be closed. The bypass line L2 is or will be closed or opened, in particular as a function of the coolant and/or an oil temperature.

In a step S160 following step S150, the ECU 9 checks if the coolant temperature T_(cool) undershoots a preset seventh limit value T_(thld5)-T_(Hyst), which, as indicated by “-T_(Hyst)”, is smaller by a hysteresis deduction T_(Hyst) than the sixth limit value T_(thld5). If this is the case (S160: “Y”), the ECU 9 switches over into the warming-up operating mode by returning to step S70. Otherwise (S160: “N”) it proceeds with step S170. In the same it checks if a fifth warming-up condition is fulfilled by checking as in step S100 if the coolant temperature T_(cool) exceeds the preset third limit value T_(request)-T_(thld6) or the torque M exceeds the torque limit value M_(thld) or the rotational speed n exceeds the rotational speed limit value n_(thld) or the travelling speed v exceeds the travelling threshold v_(thld). Here, exceeding one of these limit values is already sufficient again for the fifth warming-up condition to be fulfilled (T_(cool)>T_(request)-T_(thld6) OR M>M_(thld) OR n>n_(thld) OR v>v_(thld)).

If the fifth warming-up condition is fulfilled (S17 “Y”), the ECU 9 switches over into the closed-loop control mode by continuing with step S60. Otherwise (S170: “N”) it returns to step S150 and continues executing the heater operating mode.

In steps S120, the ECU 9 checks if a fourth warming-up condition is fulfilled by checking if the coolant temperature T_(cool) undershoots a preset fourth limit value T_(thld5)-T_(Hyst). As is evident from the designation, the same corresponds to the seventh limit value. If the ECU 9 in step S120 detects that the fourth warming-up condition is fulfilled (S120: “Y”), it returns to step S70 and again executes the warming-up operating mode, otherwise (S120: “N”) it returns to step S90 and continues executing the second warming-up operating mode.

In a step S130 following step S60, the ECU 9 checks if the internal combustion engine 1 continues operating or is fueled. For as long as this is the case (S130: “Y”), it remains in the closed-loop control mode. If by contrast the ECU 9 in step S130 determines that the internal combustion engine 1 is no longer running or (has been) switched off (S 130: “N”), it proceeds with step S140 in which it operates the coolant pump 2 for a preset period of time following the shutting off of the internal combustion engine 1. This period of time and/or the rotational speed of the coolant pump 2 can be preset in an embodiment fixed or variably, in particular as a function of a temperature, in particular of an ambient, coolant, internal combustion engine and/or motor vehicle temperature.

Following this, i.e. after expiration of this preset period of time, the ECU 9 or the method returns to step S10.

While at least one exemplary embodiment has been presented in the foregoing detailed description, it should be appreciated that a vast number of variations exist. It should also be appreciated that the exemplary embodiment or exemplary embodiments are only examples, and are not intended to limit the scope, applicability, or configuration of the invention in any way. Rather, the foregoing detailed description will provide those skilled in the art with a convenient road map for implementing an exemplary embodiment, it being understood that various changes may be made in the function and arrangement of elements described in an exemplary embodiment without departing from the scope of the invention as set forth in the appended claims and their legal equivalents. 

1-15. (canceled)
 16. A method for operating a cooling system with a coolant pump for an internal combustion engine comprising: operating the coolant pump for a preset period of time after a starting of the internal combustion engine; and switching-over the cooling system after the preset period of time into a first warming-up operating mode in which the coolant pump is not operated when a first warming-up condition is fulfilled.
 17. The method according to claim 16 further comprising switching the cooling system over from the first warming-up operating mode into a closed-loop control mode, wherein at least one of the coolant pump and a control valve of the cooling system is closed-loop controlled when the first warming-up condition is not fulfilled.
 18. The method according to claim 17, further comprising switching the cooling system over from the first warming-up operating mode into either he closed-loop control mode or a second warming-up operating mode when a second warming-up condition is
 19. The method according to claim 18, wherein the second warming-up operating mode comprises operating the coolant pump in one of a pulsed mode or with a preset rotational speed.
 20. The method according to claim 18, further comprising: switching the cooling system over from the second warming-up operating mode into the closed-loop control mode when a third warming-up condition is fulfilled; and switching the cooling system over from the second warming-up operating mode into the first warming-up operating mode when a fourth warming-up condition is fulfilled.
 21. The method according to claim 16, further comprising checking an operational state of the control valve.
 22. The method according to claim 16, further comprising operating the coolant pump for a preset period of time after a switching-off of the internal combustion engine.
 23. The method according to claim 16 further comprising fulfilling at least one warming-up condition when at least one of a coolant or a reference temperature crosses a preset limit value.
 24. The method according to claim 16 further comprising fulfilling at least one warming-up condition when a parameter of the internal combustion engine or of a motor vehicle with the internal combustion engine exceeds a preset limit value.
 25. A computer program product comprising a non-transitory computer readable medium having a program code stored thereon which when executed on a controller carries out the method according to claim
 16. 26. A cooling system with a coolant pump for an internal combustion engine comprising a controller configured to: operate the coolant pump for a preset period of time after a starting of the internal combustion engine; and switch over the cooling system after the preset period of time into a first warming-up operating mode in which the coolant pump is not operated when a first warming-up condition is fulfilled.
 27. The cooling system according to claim 26 wherein the controller is further configured to switch the cooling system over from the first warming-up operating mode into a closed-loop control mode, wherein at least one of the coolant pump and a control valve of the cooling system is closed-loop controlled when the first warming-up condition is not fulfilled.
 28. The cooling system according to claim 27 wherein the controller is further configured to switch the cooling system over from the first warming-up operating mode into either he closed-loop control mode or a second warming-up operating mode when a second warming-up condition is fulfilled.
 29. The cooling system according to claim 28, wherein the controller is configured to operate the cooling pump in one of a pulsed mode or with a preset rotational speed for the second warming-up operating mode.
 30. The cooling system according to claim 28, wherein the controller is further configured to switch the cooling system over from the second warming-up operating mode into the closed-loop control mode when a third warming-up condition is fulfilled, and switch the cooling system over from the second warming-up operating mode into the first warming-up operating mode when a fourth warming-up condition is fulfilled.
 31. The cooling system according to claim 26 wherein the controller is further configured to check an operational state of the control valve.
 32. The cooling system according to claim 26, wherein the controller is further configured to operate the coolant pump for a preset period of time after the internal combustion engine is switched off.
 33. A motor vehicle comprising an internal combustion engine and a cooling system according to claim
 26. 